Rotational stocking requires pastures to be subdivided into individual grazing units called paddocks. The size and number of paddocks depend on the level of pasture productivity, stocking rate of livestock, and the desired residency period. Individual paddocks are grazed one at a time, in a planned order, with livestock occupying each paddock long enough to harvest the existing forage, but not so long as to allow grazing of regrowth to occur. After each paddock is grazed to the desired forage stubble height (which depends on the plant species and grazing prescription), the pasture is allowed to regrow and regain vigor before again being grazed.
In a well-managed rotational stocking method, the forage supply is constantly monitored and adjustments to the stocking rate made by increasing or decreasing the amount of pasture acreage grazed during a particular time period.
Generally, development costs for water, fence, and management are greater for rotational stocking than for continuous stocking. However, because it is easier to maintain an effective balance between forage demand and forage supply, rotational stocking methods generally promote higher forage yields, more uniform levels of forage quality, improved harvest efficiencies, and as a result, maximize livestock production per acre of pasture.
Another advantage of using the rotational stocking method is that by controlling the frequency and intensity of grazing, plant species which are capable of producing higher forage yields can be utilized. With continuous stocking, the taller more productive plant species tend to decline in productivity and abundance. With the rotational stocking method, these plants can remain productive and persistent for many years.
The Use and Management of Rotational Stocking Methods
Generally, rotational stocking methods provide the greatest benefit for lactating dairy cattle and livestock with superior genetics for growth. These types of animals have the greatest need for large quantities of consistently high quality feed in order to maximize their genetic potential. Livestock operations seeking to maximize production per acre of pasture will also benefit from pastures grazed with a rotational stocking method.
In most instances livestock should not remain on an individual paddock for longer than 7 days, with 3-4 days a more preferred residency period. The exception to this occurs with lactating dairy cows. In order to maintain consistency of milk production, they should not remain in one paddock for longer than 2 days, with a half day residency period preferred. Although there are no optimum rest intervals between grazing periods, it is recommended that during the most active growth periods of spring and early summer, once a paddock is grazed it should be rested between 15 and 20 days, and during the slower growth periods of late summer and fall between 20 and 40 days.
The rotational stocking method is planned around having enough forage available for grazing during the mid-summer period. As a result, during the spring there will be nearly twice as much forage as the livestock need for grazing.
Hence, approximately 50 percent of the planned acreage should be closed for grazing during the first two months of the pasture season and the surplus forage mechanically harvested or grazed with other livestock accounted for in the planning process. Once the forage growth rates begin to decline and there is a need for additional feed, the entire planned acreage will become available for grazing.
The continuous stocking method is a method of livestock deployment where livestock have the continuous or uninterrupted use of a unit of pasture throughout the time period in which grazing is allowed.
As commonly practiced, the continuous stocking method can be described as a minimum management practice. A set number of animals are turned out on a given number of acres of pasture and allowed to graze for as long as the forage supply lasts. Although development costs for water and fencing are low with this method, it is extremely difficult to control the grazing events, and thus, it is nearly impossible to maintain an effective balance between forage demand and forage supply. When stocking rates are set too high, animal nutritional requirements are not met and individual animal performance is reduced. When stocking rates are set too low, forage is wasted and production per acre is reduced. In either case, the result is often a highly variable forage quality and an inefficient conversion of forage into a saleable product.
Generally, the continuous stocking method is not very productive in terms of liveweight gains per acre or in maximizing the length of grazing season. However, as long as there is an adequate supply of forage, gains per animal are often equal to or greater than those obtained from more intensively managed rotational stocking methods. This is primarily the result of selective grazing.
When provided with a surplus of forage from which to choose, grazing animals have the ability to select a diet that is higher in overall quality than the average quality of the pasture. In other words, they select the best and leave the rest. Unfortunately, the forage that is left behind is wasted, and it is this non-utilized feed that accounts for the reductions in liveweight gains per acre and length of grazing season.
Another problem with continuous stocking is that over time it can weaken or eliminate many of the more productive plant species. Forages such as birdsfoot trefoil, red clover, alfalfa, bromegrass, timothy, and orchardgrass do not survive well under close continuous grazing. As a result, pasture yields are often reduced along with a loss of quality.
The Use and Management of Continuous Stocking Methods
Because of the increased amount of wasted forage associated with the continuous stocking method and the highly variable forage quality, it is not recommended for livestock operations where maximizing production per acre is the primary objective or for livestock possessing high genetic potentials for growth or milk production. However, for many livestock operations where the forage supply exceeds the forage demand, and there is no demonstrated need for the surplus forage, continuous stocking may be the most appropriate method or all that can be economically justified.
An improved management strategy for increasing the harvest efficiency of pastures which are continuously stocked is to alter the number of grazing animals in response to the amount of available forage. This is generally described as a “put and take” style of grazing management. Although pastures that are managed using this strategy may be continuously stocked during the period of time in which grazing is allowed, the forage supply is constantly monitored and adjustments to the stocking rate made by increasing or decreasing the number of grazing animals in response to the available forage supply.
In the spring of the year, pastures should be stocked with approximately twice the expected summer stocking rate. As forage growth rates slow in midsummer, the stocking rate should be reduced by at least 50%.
This method is particularly effective if there are haylands available which can be grazed after the first cutting of hay is taken, or when animals of different age classes are grazed together and some of the animals can be sold, placed in feedlots, or in some other manner removed from the pasture.
With the continuous stocking method, there are always some livestock present on a pasture during the time period in which grazing is allowed. As a result, there is very little opportunity to directly control the frequency and intensity of grazing events. Therefore, it must be done indirectly by establishing grazing height guidelines. During the grazing period, the height of the forage should not be allowed to exceed six inches nor decrease to less than three inches.
Another use for the continuous stocking method of grazing is where the prescribed grazing objective is to weaken or eliminate a particular plant or plant community. By overstocking a unit of pasture and grazing with the continuous stocking method, grazing and browsing animals can harvest vegetation with a frequency, intensity, duration, and timing that is not conducive to its continued survival. Once the plant community is weakened or suppressed, the pasture can be over-seeded with a more desirable plant species.